Cetiosaurus
Cetiosaurus (SEET-ee-oh-sawr-us) meaning 'whale lizard', from the Greek cetus/κητος meaning 'sea monster' (later, 'whale') and saurus/σαυρος meaning 'lizard', was a sauropod dinosaur from the Mid to Late Jurassic Period (181-169 million years ago) in what are now Europe and Africa. It is estimated to have been about 53 feet (16 m) long and to have weighed roughly 24.8 tonnes (27.3 short tons). It was so named because its discoverer, Sir Richard Owen supposed it was a marine creature, initially an extremely large crocodile. It was a primitive, quadrupedal, long-necked, small-headed herbivore, with a shorter tail than most sauropods. Description Cetiosaurus was a long-necked quadrupedal animal approximately 18 meters (59 ft) long. Its neck was as long as its body, and the tail was considerably longer, consisting of at least 40 caudal vertebrae. Its dorsal vertebrae, the bones along the back, were heavy and primitive, unlike the hollowed-out bones of advanced sauropods like Brachiosaurus. Its forearm, too, was as long as the upper arm, unlike most other sauropods. Its thigh bone was approximately six feet in length. Discovery and species Cetiosaurus was the first sauropod to be discovered and named as well as being the best known sauropod from England. Fossilized remains have been found in England and Morocco. Remains consisting of a vertebra, rib and arm bone had been discovered on the Isle of Wight and named by English biologist, comparative anatomist and palaeontologist Sir Richard Owen, in 1841, the year before he coined the term Dinosauria. More limb bones were found in the late 1840s and a fairly complete skeleton in 1868. Owen thought it had crocodilian features. Ironically, Cetiosaurus's true nature was not realized until Thomas Huxley named it as a dinosaur in 1869. Numerous species have been assigned to Cetiosaurus over the years and belong to several different groups of dinosaurs. The best known of these is C. oxoniensis, from the Middle Jurassic (Bajocian) of Oxfordshire and Rutland, However, the type species is C. medius, known from undiagnostic material (note that Upchurch and Martin 2003 reported C. brevis as the type species, but no longer hold this view; the problem stems from the fact that Richard Owen described four species in the same paper and did not designate one as the type). To improve this situation, Upchurch and colleagues have proposed making C. oxoniensis the type species of Cetiosaurus, which will retain the name Cetiosaurus for the animal with which it has been traditionally associated. Classification The closest relatives of Cetiosaurus appear to be Barapasaurus and the South American Patagosaurus. Together they comprise the Cetiosauridae, which was previously a large ill-defined family of primitive sauropods. It must also be noted that Chebsaurus is often referred to the Cetiosauridae, and that Barapasaurus has been assigned to the Vulcanodontidae, due to its having cervical vertebrae that resemble other cetiosaurids, but a narrow sacrum that is a defining factor for vulcanodontids. Paleobiology It shared its time period with, and was possibly prey to, Megalosaurus and Eustreptospondylus. The environment in which Cetiosaurus lived was floodplain and open woodland. Category:Dinosaurs Category:Extinct Reptiles and Amphibians Category:Vertebrates Category:Chordata Category:Extinct in Britain Category:Saurischian